Problem 1 (10 pts) Cryptanalysis against Encryption Modes (4 pts) Suppose that everyone in the world is using the DES algorithm in the ECB encryption mode, and you can use a chosen plaintext attack against everyone. Show how to perform a dictionary attack such that, after an expensive initialization step, everyone's key can be recovered in very little time. Write pseudo code both for the initialization step and for the function to recover everyones key. (2pts) How effective would the above attack be if AES, instead of DES, is used? (2pts) How effective would the above attack be under known-plaintext (instead of chosen plain- text) attacks? (2pts) How effective would the Chosen Plaintext attack described above be if everyone uses the CBC encryption mode with the IV randomly chosen? Problem 1 (10 pts) Cryptanalysis against Encryption Modes (4 pts) Suppose that everyone in the world is using the DES algorithm in the ECB encryption mode, and you can use a chosen plaintext attack against everyone. Show how to perform a dictionary attack such that, after an expensive initialization step, everyone's key can be recovered in very little time. Write pseudo code both for the initialization step and for the function to recover everyones key. (2pts) How effective would the above attack be if AES, instead of DES, is used? (2pts) How effective would the above attack be under known-plaintext (instead of chosen plain- text) attacks? (2pts) How effective would the Chosen Plaintext attack described above be if everyone uses the CBC encryption mode with the IV randomly chosen